User manual

Chapter 3 Signal Conditioning Application Examples
 National Instruments Corporation 3-3 BNC-2090 User Manual
Soldering and Desoldering on the BNC-2090
Some applications require you to modify the PWB, usually by removing
0 Ω jumpers and adding components. The BNC-2090 is shipped with
0 Ω jumpers in the C and D positions (see Table 3-1 and Figure 3-2).
Use vacuum-type tools when desoldering on the BNC-2090 and avoid
damaging component pads.
Use a low-wattage soldering iron (20 to 30 W) when soldering to the
board. You should use only rosin-core, electronic-grade solder. Acid-
core solder damages the printed circuit board and components.
Analog Input
Each analog input signal has several open positions for passive signal
conditioning components. Four of these positions are designated as
resistors and one is designated as a capacitor. The factory-default
positions for the 0 Ω jumpers are the C and D positions of the input
network, as shown in Figure 3-2. You can remove these 0 Ω jumpers to
build analog input signal conditioning circuits. You can also add
passive analog input signal conditioning, such as filters and dividers.
The component positions are different for each channel. Figure 3-2
shows the onboard equivalent circuit.
Table 3-1. Channel Component Positions
Channel
Position in Figure 3-2
Differential Single-Ended A B C D E
0
0, 8 R1 R2 R19 R20 C1
1 1, 9 R3 R4 R21 R22 C2
2 2, 10 R5 R6 R23 R24 C3
3 3, 11 R7 R8 R25 R26 C4
4 4, 12 R9 R10 R27 R28 C5
5 5, 13 R11 R12 R29 R30 C6